This disclosure relates to controlled drug delivery, particularly implantable devices that can be deployed within the bladder or another site in a patient for controlled drug release.
U.S. Patent Application Publications No. 2007/0202151 and No. 2009/0149833 describe drug delivery devices for minimally invasive deployment and retention in a cavity or lumen in a patient, such as the bladder. The devices resist excretion, such as in response to the forces associated with urination. For example, the devices may include a retention frame, which may be configured into a relatively low profile for deployment into the body, and once implanted may assume a relatively expanded profile to facilitate retention. The devices may provide controlled release of drug over an extended period in a predefined manner. In some embodiments, the devices include a water-permeable silicone tube that defines a drug reservoir for housing a drug and at least one aperture for releasing the drug. The drug may be a highly water soluble drug, such as lidocaine hydrochloride in solid form, and the in vivo drug release mechanism may be partially or predominantly an osmotic pumping mechanism. It would be desirable to provide additional techniques, structures, and/or formulations to enhance control of drug release kinetics in vivo, for example from a device deployed in the bladder.